A hydra prophet? That's even weirder, thematically, than the Ashikaga Jonin prophet I had in one game. Heh -- with over 60+ assassinations (long, slow-paced SP game) I reckon he'd be good at keeping the audience's attention.
(And I'm tempted to try out an Arco Golden Era Sceptic Prophet, both for the irony and for the hope that it would tear down enemy dominion especially fast.)